feat: support numeric image IDs for snapshots

GetByNameAndArchitecture only works for named images.
Hetzner snapshots have no name — only a numeric ID.

If DISK_IMAGE is a numeric string, look up by ID directly
using Image.GetByID. Otherwise fall back to the existing
name+architecture lookup.

This allows users to boot DevPod workspaces from a
pre-baked Hetzner snapshot, skipping slow provisioning steps.

Author: aaronshaf

pkg/hetzner/hetzner.go

@@ -143,9 +143,19 @@ func (h *Hetzner) BuildServerOptions(
 		// Machines starting "cax" are ARM64
 		arch = hcloud.ArchitectureARM
 	}
-	image, _, err := h.client.Image.GetByNameAndArchitecture(ctx, opts.DiskImage, arch)
-	if err != nil {
-		return nil, nil, nil, err
+
+	var image *hcloud.Image
+	if id, err := strconv.Atoi(opts.DiskImage); err == nil {
+		// Numeric ID — look up directly (supports snapshots, which have no name)
+		image, _, err = h.client.Image.GetByID(ctx, id)
+		if err != nil {
+			return nil, nil, nil, err
+		}
+	} else {
+		image, _, err = h.client.Image.GetByNameAndArchitecture(ctx, opts.DiskImage, arch)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 	}
 	if image == nil {
 		return nil, nil, nil, ErrUnknownDiskImage